I like the recycling of codes because #1, it makes it faster and easier and #2 it saves money from having multiple programmers make a new one because you just need to edit and revise some lines of codes.
I'd like to add a what if. What if we make this burning events a more common occurrence? You could also do something along the line of burning cards to get a pack. let's say establish points for common, rare, epic and legendaries and then when you get to a certain point, you can use that to buy packs.
Reason for this is to reduce the number of cards on the market specifically CHaos Legion packs. Djinn Oshannus is an awesome card and you can see it sold for less than $1 because of how ridiculously many is it right now on the market.
By doing this, players can technically discard the cards that they don't want in hopes to get a better one. Also it reduces the cards in the market. Let's say you need to burn 500 common cards in total to get 1 Chaos legion pack (5 cards in total). If you can get 4 commons in that CL pack, then a 496 card were just burned. If 10 people do this 10 times, then you have 49600 common cards burned for a 400 common card (considering the CL pack they get are worsts by having 4 common 1 rare. CL packs would still be random in chance like a normal pack.)
TLDR, it's just recycling cards to get better cards (hopefully), while reducing the overall number of cards in the market which is waaaaaaayyy above the active playerbase right now.